Prediction of brain age and cognitive age: quantifying brain and cognitive maintenance in aging

Abstract

The concept of brain maintenance refers to the preservation of brain integrity in older age, whilecognitive reserverefers to the capacity to maintain cognition in the presence of neurodegeneration or aging-related brain changes. While both mechanisms are thoughtto contribute to individual differences in cognitive function among older adults, there iscurrently no ‘gold standard’ for measuring these constructs. Using machine-learning, weestimated brain and cognitive maintenance based on deviations from normative agingpatterns in the Whitehall II MRI sub-study cohort, and tested the degree of corre-spondence between these constructs, as well as their associations with premorbid IQ,education, and lifestyle trajectories. In line with established literature highlighting IQas a proxy for cognitive reserve, higher premorbid IQ was linked to cognitive mainte-nance independent of the degree of brain maintenance. No strong evidence was found forassociations between lifestyle trajectories and brain or cognitive maintenance. In con-clusion, we present a novel method to characterize brain and cognitive maintenance inaging, which may be useful for future studies seeking to identify factors that contributeto brain preservation and cognitive reserve mechanisms in older age